casper



F. T. CASPER.

ELECTROMAGNETIC DEVICE.

APPucATioN man APR. 2. 19u.

1,318,878. PatentdAug. 26,1919.

2 SHEETS-SHEET 1.

F. T. CASPER.

4 ELECTROMAGNETIC DEVICE.

APPLlcATloN FILEn APn.2.I1911.

1,313,878, PatentedAug-26, 1919.

2 SHEETS-SHEET 2. FIG. 3.v

UNITED STATES PATENT OFFICE.

FRANK T. CASPER, OF GATES, NEW YORK, ASSIGNOB. TO GENERAL RAILWAY SIGNAL COMPANY, OF GATES, NEW YORK1 A CORPORATION OF NEW YORK.

ELECTROMAGNETIC DEVICE. i

Specicationof Letters Patent.

Patented Aug. 26, 1919.

Application led April 2, 1917. Serial No. 159,201.

To aZZ whom it may concern:

Be it known that I, FRANK T. CASPER,

. a citizen o f the United States, and resident of the town of Gates, in the county of Monroe and State of New York, have invented a new and useful Electromagnetic Device, of which the following is a specification.

This invention relates to electric interlocking systems in which the functions are operated by alternating current| and automatically generate direct current for indication purposes, and has for its principal object the production of a simple and reliable indication magnet which will give the desired operation under the influence of direct current but which will not be affected by alternating current or other periodic iuctuating current.

Other objects and advantages will appear more fully hereafter in the description of the particular embodiment of the invention selected to explain its principles, mode of operation and features of construction; and the novel features of the invention will be pointed out in the appended claims.

In describing the particular embodiments of the invention disclosed herein, reference is made to the accompanyin drawings which form part of this specification, in

' which like reference characters refer to like parts in the several views, and in which:

Figure 1 is a top lan view of an indication magnet embodying this invention;

Fig. 2 is a side view, partly in vertical section, of the indication magnet shown in Fig. 1;

Fig. 3 isa simple circuit illustrating the manner in which the indication magnet shown in Figs. 1 and 2 is used in connection with one type of an interlocking system.

Referring to the accompanying drawings, the invention has been shown embodied in an electromagnet especially applicable for use as an indication magnet in electric interlocking systems of the type in which alternating current is used for operating purposes and in which direct current is used for indication purposes; but it is to be clearly understood that electromagnets may be con structed in accordance with this inventionl cores 2 being made of iron or other magnetic material according to the well known pract1ce. In the lower end of each core 2 is a screw 3 which serves to fasten a residual washer 4 of brass or other non-magnetic material, and an iron pole ,piece 5 to the end of the core, said screws 3 being preferably connected by a locking wire 6 which prevents the accidental loosening of these screws after they have once been adjusted. The armature 7` of the indication magnet lis guided at its ends by the screws 3, and is connected to the lower end of a plunger 8 which extends upward through acounter-sunk hole 9 in the yoke 1 and terminates in a hardened head 10 which is adapted to operate any suitable form of indication mechanism.

Oneach core 2 is a winding or coil 11 which is made much shorter than the core.2 and which is held in place thereon by a coilsupportin collar or ring 12 fastened to the correspon ing core 2 by a pin 13 or other suitable means. The leads 141 of the coils are-preferably disposed in channels formed by grooves in the upper face lof a block 15 of ber or other insulating material and a cover strip yof insulatin material 16, the block 15 and strip 16 being placed between the upper ends of the coils 11 and the yoke 1. On each coreI 2 below its corresponding winding or coil 11 is a sleeve or collar 17 formed of copper or other suitable electrical non-magnetic conducting material, this sleeve being preferably somewhat shorter than the space between the coil support 12 and the pole piece 5 so as to leave a space between its upper end and said coil support 12.

When direct current is supplied to the windings or coils 11 of the indication magy net shown in Figs. 1 and 2, the armature 7 is attracted in the usual way; but when alternatin current is Supplied to said coils alternating current is induced in the copper sleeves 17 in analogy to the well known transformer action. This current induced in the copper sleeves 17, according to the well known law of induced currents, tendsi to oppose the alternatingl flux setting up this induced current, so t at the reluctance of the path through the lower portions of the cores 2, the air gaps between said cores and the amature 7 and through the armature 7 is greatly increased, thereb causing a great increase in the leakage o the ilux between the coils 11. In other words, the al- 'l device to be deranged by the mere 30 ternating flux set up -by the flow of alternating-` current through the coils 11 is so greatly `opposed or choked back by the copper sleeves 17 from passing through the armature 7, that this flux takes the leakage paths directly from core to core without passing through said armature. If found necessary or desirable, the reluctance of the leakage paths may be decreased by making the coil magnetic material in order that the leakage iux may not have an influence upon this plunger and cause a false operation. In this connection, it has also been found by experiment that it is preferable to have a space between the lower end of each coil or winding 11 and copper sleeve 17, although it is to be understood thatthe adoption of this expedient depends upon the characteristics and features of the particular design of the electromagnet. Since the copper sleeves 17 which constitute the agency for preventing the operation of the device by alternating current, are solid and substantial members, there is no opportunit for the breaking or disconnection of wires. For this .reason the use of copper sleeves 17, which are in effect a single conductin turn, is referred although it is to be un erstood t at a co' of several turns, short circuited on itself,

ymay be used with the same effect and for the same purpose. l

From the foregoing it can be seen that lthere is provided according to this invention a simple and reliable electromagnetic device whlch is capableof being operated by direct current but which is not affected by alternating current or a similar periodic' iuctuating current. The applications and uses of suchan electromagnetic device are obviously very numerous in the electrical art, and in Fig. 3 there is illustrated a simple circuit showing how the electromagnetic device embodying this invention may be ap-l1 -plied to an alernating current interlocking system. In Flg. 3 there is shown diagrammatically and in accordance with established conventions, a circuit for electric interlocking which in some respects is the same as the circuit usedl in the welly known system of electric interlocking usin dynamic indication. Since the constructlon and operation of the various parts in this system are well known to those skilledv in the art and are vshown and described in the published art, it is unnecessary to illustrate and describe the construction of these parts in detail. The reference character L designates as a whole the usual lever and its associated contacts. The reference character F designates as a whole the parts associated with lthis type of interlockin `nalaat/e the switch machine or other function, which in general comprises a'motor having a field 18 land an armature 19, and a pole changer 20. The motor is of some suitable type which can be operated by alternating current and which is capable of generating dynamically a direct current after each operation of the function. The reference character T designates a transformer which constitutes the source of supply ofl current used for operating the system; and the letter I indicates the indication magnet constructed-as shown in'Figs. 1 and 2. The operation of the interlocking system shown in Fig. 3 will be ,clearly understood by tliose skilled in the art, especially in connection with the description in the patents hereinbefore mentioned, without further explanation.

' The indication` magnet, constructed as shown in Figs. 1 and 2, so that it will be operated on direct current but not by alternating current, is especially adapted to of the fact that certain rangements of the system, such as crosses between certain wires, and the like, may 'result' in the'current from the operating source T being improperly applied to the'indication magnet I at a time when the operation of this indication magnet would resultgin the giving of a false indication. With an indication magnet constructed according to this invention,.however, the possibility of such a false indication being glven is entirely avoided, and regardless of the way in which alternating current Vfrom the operating source T is improperly'permitted to iiow through the indication magnet I, an operation of the indication magnet cannot be produced under any circumstances, so that an interlocking system including an indication magnet constructed according to this invention is thoroughly safe-guarded against false indication by current derived from the operating source. 'l

Although I have particularly described the construction of one .physical embodiment of my invention, and explained the operation and principle thereof; nevertheless, I desire to have it understood that the form selected is merely illustrative, but does not exhaust the possible physical embodiments i i system by reason of the ideaof means underlying my invenf tion. What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electric interlocking system, the combination with an electrically operable flmction having amotor adapted to operate on alternating current and to nerate direct current dynamically, of` indication mechanism', and an electromagnet for operating y said indication mechanism having a short circuited coil which is arranged in inductive relation to each operating Winding and 180' which is locatedbetween its armature and ectromagnetic device comprising a yoke,

cores and a movable armature constituting a magnetic circuit, an -operating coil on each core, and a sleeve of electrical conducting material surrounding each core between its operating coil and said armature.

3. In an electric interloclnng system, the combination with an electrically operable function a motor adapted to operate on alternating -currentand to generate direct current dynamically, of indication mechanism, an e c device for said indication m com prising a eoreand a movable armature constituting a magnetic circuit, a winding assoated with the core, and acop alte recoreactingnpono mating flux through the core for opposing the passage of flux through the armature, whereby the indication mechanism will be operated by the direct current nerated dynamically bg' the function but will not be operated byl t e alternation current derived from any improper electrical connection to the source of operating current. 4

4. In an electric interlockin system, the

combination with an electri l operable function having a motor adap to operate on alternating current and to crate direct current dynamically, of indication mecha- 4o nism comprising an operating winding, a

core, a movable armature, and means forming a short circuited conducting path dis posed in inductive relation to the operating winding between it and the armature.

5. In an electric interlocking system, the combination with an electrictaly operable function having a motor adap to operate on alternating current and to generate direct sleeve on,

' rect current ynamically, of an electromagcurrent dynamically, of an electromagnetic indication device comprisin a core and a movable armature constituting a circuit having leakage paths, an operating winding associated with the core, and protective means arranged in inductive relation. to the operating wmdinoand acting to cause 56 a diversion of the flux in the armature to the leakage paths upon the flow of alternatcurrentinthe opera vwin ding. 6. In an electric mterloc system, the

combination with an electrically operable 60V function having a motor adapted to operate on alternating current and to nerate direct current dynamically, of an e ectromagnetic indication device comprising a core and a movable armature, an operating winding 66 associated with the core, said core extending beyond the ends of said winding, and sleeves of electrical conductin material surroundthe core between t e amature and said win ding.

7. In an electric interlocking system, the combination with an electrically operable function having a motor adapted to operate on alterna current and to generate dinetic indication device comprising two cores connected by a yoke, an operating winding on each core, said cores beyond the ends of the o rating windings, a sleeve' of electrical con u material surrounding the extending portion of each core with a s ace between the sleeve and the winding, and a movable armature associated with the ends Iof the iliores. l tha 8. n an e ectric inter syst 86 combination with an electrically oemiable function adapted to be pperated by a ternatinlcurrent and employing direct current for in 'cation p of an indication magnet comprising a core and a movable armature 90 constitnt' a magnetic circuit, an o rating winding 1dlgthe core, and a sleeve ofeelectrimaterial surrounding the e armature and the operating FRANK T. CASPER.

lcal conductin core between winding. 

